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Photoredox catalysis has experienced a revitalized interest from the synthesis community during the past decade. For example, photoredox/Ni dual catalysis protocols have been developed to overcome several inherent limitations of palladium-catalyzed cross-couplings by invoking a single-electron transmetalation pathway. This Perspective highlights advances made by our laboratory since the inception of the photoredox/Ni cross-coupling of benzyltrifluoroborates with aryl bromides. In addition to broadening the scope of trifluoroborate coupling partners, research using readily oxidized hypervalent silicates as radical precursors that demonstrate functional group compatibility is highlighted. The pursuit of electrophilic coupling partners beyond (hetero)aryl bromides has also led to the incorporation of several new classes of C(sp 2 )-hybridized substrates into light-mediated cross-coupling. Advances to expand the radical toolbox by utilizing feedstock chemicals (e.g., aldehydes) to access radicals that were previously inaccessible from trifluoroborates and silicates are also emphasized. Additionally, several organic photocatalysts have been investigated as replacements for their expensive iridium- and ruthenium-based counterparts. Lastly, the net C-H functionalization of the radical partner in an effort to improve atom economy is presented. An underlying theme in all of these studies is the value of generating radicals in a catalytic manner, rather than stoichiometrically.

An iridium photocatalyst and visible light facilitate a room temperature, nickel-catalyzed coupling of (hetero)aryl bromides with activated α-heterosubstituted or benzylic C(sp 3 )-H bonds. Mechanistic investigations on this unprecedented transformation have uncovered the possibility of an unexpected mechanism hypothesized to involve a Ni-Br homolysis event from an excited-state nickel complex. The resultant bromine radical is thought to abstract weak C(sp 3 )-H bonds to generate reactive alkyl radicals that can be engaged in Ni-catalyzed arylation. Evidence suggests that the iridium photocatalyst facilitates nickel excitation and bromine radical generation via triplet-triplet energy transfer.

Iridium- and ruthenium-free approaches to protected allylic amines and alkyl nitriles under photoredox conditions are reported. An inexpensive organic dye, eosin Y, catalyzes coupling of Boc-protected potassium α-aminomethyltrifluoroborates with a variety of substituted alkenyl sulfones through an α-aminomethyl radical addition-elimination pathway. Allylic and homoallylic amines were formed in moderate yields with high E/Z selectivity. The mechanistic approach was extended using tosyl cyanide as a radical trap, enabling the conversion of alkyltrifluoroborates to nitriles via a Fukuzumi acridinium-catalyzed process.

We report the chiral diene ligated rhodium-catalyzed dynamic kinetic asymmetric transformation (DYKAT) of racemic secondary allylic trichloroacetimidates with a variety of N-methyl anilines, providing allylic N-methyl arylamines in high yields, regioselectivity, and enantiomeric excess. The rhodium-catalyzed DYKAT method addresses limitations previously associated with this particular class of aromatic nitrogen nucleophiles.

Objective: The purpose of this paper is to present our experience with CT- and fluoroscopy-guided percutaneous nephrostomy tube (PNT) placement and to describe the technique of placement with patients in the supine-oblique position., Materials and Methods: A CT scanner was coupled with a ceiling-mounted C-arm for fluoroscopy at the CT table, PNT was done with CT localization and fluoroscopic control. We attempted 148 placements in 129 patients, with most patients in the supine or the supine-oblique position., Results: Successful PNT placement was achieved in 144 (97%) of 148 kidneys. In the native kidney group, 101 (81%) of 124 PNTs were placed with the patients in the supine-oblique position. We experienced no major complications, three (2%) minor complications, and two (1%) catheter dislodgments., Conclusion: CT-fluoroscopy control allows routine PNT placement with patients in the supine or the supine-oblique position and is associated with the lowest complication rate to our knowledge.

Objective: We prospectively compared MR imaging, MR arthrography, and CT arthrography to determine the sensitivity of each technique in detecting glenoid labral tears and in determining whether the labrum is detached or degenerated., Subjects and Methods: Thirty patients 19-39 years old (mean, 27 years old) who had either signs and symptoms of shoulder instability or shoulder pain of unexplained origin were referred for diagnostic imaging. Each patient underwent MR imaging, followed by MR arthrography after intraarticular injection of 25 ml of a dilute solution of gadopentetate dimeglumine. Twenty-eight of thirty patients underwent CT arthrography after intraarticular injection of air and radiographic contrast material. Each patient also underwent arthroscopy or open surgery., Results: At surgery, labral tears were found in 28 patients; a detached fragment was found in 26 patients. The labrum was found to be degenerated in 18. A labral tear was detected on MR images in 26 (93%) of 28, on MR arthrograms in 27 (96%) of 28, and on CT arthrograms in 19 (73%) of 26. A detached labral fragment was detected on MR images in 12 (46%) of 26, on MR arthrograms in 25 (96%) of 26, and on CT arthrograms in 13 (52%) of 25. Labral degeneration was detected on MR images in two (11%) of 18, on MR arthrograms in 10 (56%) of 18, and on CT arthrograms in four (24%) of 17. MR arthrography was the best of the three imaging techniques for showing the inferior part of the glenoid labrum and inferior glenohumeral ligament., Conclusion: MR arthrography and MR imaging both showed labral tears with greater sensitivity than CT arthrography did. MR arthrography was the most sensitive of the three techniques for detecting a detached labral fragment and labral degeneration. Furthermore, MR arthrography afforded the best visualization of the inferior part of the labrum and the inferior glenohumeral ligament. MR imaging and MR arthrography also enabled direct visualization of rotator cuff disease and other unsuspected associated abnormalities.

The authors found metastases to the heart in 10.7% of 1029 autopsy cases in which a malignant neoplasm was diagnosed. The lung was the commonest primary site (36.4%) and adenocarcinoma was the most frequent cell type (36.4%) of neoplasms metastatic to heart. Nonepithelial tumors accounted for 22.7% of cardiac metastases. Epicardium was involved in 75.5% of metastatic lesions and a pericardial effusion was present with 33.7% of epicardial metastases. Although hemorrhagic effusions occurred in only 12 cases with metastases to heart, these represented 76.4% of all such effusions. Lymphomas associated with the acquired immune deficiency syndrome showed the most extensive cardiac involvement. Primary sites and cell types of cardiac metastases have evolved over time and have been modified by chemotherapy, increased survival of cancer patients, increasing incidence of lung carcinoma, and recently by the acquired immune deficiency syndrome epidemic.